By John — Desalination News
A desalination facility in the Caofeidian industrial zone of Tangshan, in China’s Hebei province on Bohai Bay, has cut its electricity consumption by more than 60% while converting waste brine that would otherwise be discharged into the sea into a saleable industrial salt product, according to reporting this week tied to a brine pre-treatment facility operated by Tangshan Sanyou Blue Ocean Technology that has recently begun trial production.
The facility processes concentrated reject brine from the desalination process at roughly a three-to-one ratio: for every three tonnes of brine treated, it yields one tonne of “refined concentrated seawater,” at a salinity of around 120 grams per litre, alongside two tonnes of additional fresh water recovered from the stream. The concentrated output is sold on as a feedstock for chemical salt production rather than discharged as waste, turning what has long been the industry’s most intractable disposal problem into a secondary revenue stream.
Brine management has become one of the desalination industry’s most closely watched technical challenges as plants scale up. Every cubic metre of fresh water a reverse osmosis or thermal plant produces leaves behind a roughly equal volume of concentrated salt water that must be diluted and discharged, typically through an ocean outfall, at considerable energy cost and with ongoing scrutiny over its effect on marine ecosystems near the discharge point. Desalination News covered a separate Chinese plant last December that paired desalination with green hydrogen production and brine-to-industrial-use conversion, and this Caofeidian facility extends that same national push to wring additional value, rather than just a disposal cost, out of the brine stream.
The energy savings claimed at Caofeidian are substantial by industry standards — a 60% cut in electricity use, with the article’s reporting describing the facility’s consumption as having fallen by more than half, would be a significant efficiency gain for any stage of the desalination process, let alone the brine-concentration step, which is typically among the most energy-intensive parts of a zero-liquid-discharge system. The reporting does not specify exactly how much salt the Caofeidian facility produces in absolute terms, nor its overall desalination capacity, but frames the approach as capable of converting what it describes as millions of tonnes of waste brine into a usable chemical salt product over time.
China has emphasized reducing the cost and environmental footprint of desalination as it expands capacity along its water-stressed northern and eastern coastline, where heavy industry and dense coastal populations compete for limited freshwater. A brine-to-salt process that both cuts a plant’s power bill and creates a sellable byproduct addresses two of the technology’s biggest remaining cost and environmental objections at once, which is likely why Chinese outlets are framing the Caofeidian trial as a meaningful step rather than a routine efficiency upgrade.
Trial production at the facility is reportedly still in its early stages, and independent, English-language technical detail beyond this week’s reporting remains limited. Desalination News will continue to track Tangshan Sanyou Blue Ocean Technology’s progress as the brine pre-treatment process moves from trial to fuller-scale operation, and as the industrial salt output finds buyers.
(Source: South China Morning Post)